WASHINGTON — Jenrry Mejia’s first taste of the closer’s role went smoothly on Saturday.

Bartolo Colon had rolled through eight innings against the Nationals and could have continued, but manager Terry Collins saw an optimal opportunity to get Mejia his first major league save and went for it.

“We’ve got to find out,” Collins said after the Mets’ 5-2 victory over the Nationals. “We’ve got to see how this kid is going to handle it, so I put him in there.”

Mejia pitched a scoreless inning, allowing a hit and striking out two.

“I feel comfortable when I know I’m going to pitch,” said Mejia, who was told by Collins before the game to be ready.

The next test for Mejia could be pitching on Sunday, giving him back-to-back appearances for the first time since moving to the bullpen last week, but the right-hander said he will wait to see how he feels before declaring himself available.

Kyle Farnsworth, whom the Mets outrighted Wednesday, signed with the Astros on Saturday. It means the veteran reliever won’t get his wish to pitch against the Mets until possibly the final three games of the season, when the Astros visit the Mets.

Before departing, an angry Farnsworth said he wanted to find a team that plays against the Mets.

Pitching coach Dan Warthen indicated he isn’t concerned by Zack Wheeler’s recent control problems. Wheeler, who is scheduled to start Sunday’s series finale, has walked 11 batters over his last two starts. That included a career-high six against the Yankees on Tuesday.

“His delivery has been sound, he’s been throwing well in the bullpen,” Warthen said. “I think he got a little excited in the last game in Yankee Stadium and was overthrowing just a little bit. The game before in Miami he ended up having four walks the last six hitters he faced, but up to that point he was pretty good.

“The excitement, the adrenaline, got a hold of him in Yankee Stadium. A couple of calls that were pretty close and then he started to aim the ball a little bit, guide it.”

Though Wilmer Flores got the start Saturday at shortstop and went 1-for-3, Collins said he remains committed to Ruben Tejada as the starter.

“Ruben’s had some very good at-bats,” Collins said. “Just because the result isn’t necessarily hits, he’s still swung the bat real well lately — worked the count and gotten on base and things we’ve wanted him to do. And he’s played outstanding defensively. He’s getting to be the guy we know.”

Is Mejia the Mets' new closer?

Got to keep the .189 hitting Tejada in the line-up at all costs. To get Flores some at-bats he'll sit Murphy against a lefthander . Murphy is hitting .359 vs. lefties this year, .290 lifetime. Yeah, that makes sense bench our best hitter for a game because you want to keep Tejada's bat in the line-up. Is Collins a drunk?